Recent technological advancements have led to the creation of a new interactive medium, the interactive video display system. Interactive video display systems allow real-time unencumbered human interactions with video displays. Natural physical motions by human users are captured by a computer vision system and used to drive visual effects. The computer vision system usually uses images captured by a video camera as input and has software processes that gather real-time information about people and other objects in the scene viewed by the camera.
One type of vision system creates a background model for distinguishing between foreground and background objects of captured images. The real world environment is very dynamic. As a result, the background model developed from the camera input image may vary over time. For example, the overall lighting of the image viewed by the camera can change, scuff marks or other discolorations can appear, objects may be left on the screen, and specular reflected light from the sun or other sources can move or change, among other things. Consequently, the vision system needs to distinguish important changes in the image from other ones.
In certain situations, the vision system may be subjected to rapid environmental changes that effect the captured image. Such rapid changes can occur, for example, due to people turning lights on and off in a room as well as the sun going behind a cloud, a janitor cleaning the screen, or a change in the display surface material. Since most lighting changes affect the entire screen, the effect on the vision system as described so far would be catastrophic. For instance, with typical parameter settings, the entire screen would appear as foreground for several minutes, causing whatever software using the vision output image to behave in an unusable and erroneous manner.
In other situations, the vision system may treat an object as a foreground object when it should be treated as part of the background. For example, if a person sets an object down, and the object does not move for several minutes, the vision system still considers the object as part of the foreground until it is slowly learned into the background. As such, the vision system continues to react to the object is if it were in the foreground, distracting the viewers.